Image processing apparatus with an improved table image detecting unit

Abstract

An image processing apparatus includes an area extracting unit and a table image detecting unit. The area extracting unit is configured to extract halftone dot areas and character images in an image. The table image detecting unit is configured to detect the extracted halftone dot areas as a table image if (a) the extracted halftone dot areas include no ruled lines, (b) plural halftone dot areas among the extracted halftone dot areas are arrayed in a primary scanning direction and/or a secondary scanning direction, and (c) the arrayed plural halftone dot areas include the character images at at least two positions.

What is claimed is: 
     
       1. An image processing apparatus, comprising:
 an area extracting unit configured to extract halftone dot areas and character images in an image; 
 a table image detecting unit configured to detect the extracted halftone dot areas as a table image if (a) the extracted halftone dot areas include no ruled lines, (b) plural halftone dot areas among the extracted halftone dot areas are arrayed in a primary scanning direction and/or a secondary scanning direction, and (c) the arrayed plural halftone dot areas include the character images at least two positions; 
 a compression processing unit configured to identify other parts than the detected table image and the character images as a background image, and independently compress the detected table image, the character images and the background image in a predetermined coding method; and 
 a file generating unit configured to generate a file that includes the compressed table image, the compressed character images and the compressed background image in respective layers. 
 
     
     
       2. The image processing apparatus according to  claim 1 , wherein the compression processing unit is further configured to convert colors of each cell, each column or each row in the table image to a single color and compress the table image that has the changed color. 
     
     
       3. An image processing apparatus, comprising:
 an area extracting unit configured to extract a halftone dot area and a character image in an image; 
 a table image detecting unit configured to detect the extracted halftone dot area as a table image if (a) the extracted halftone dot area includes no ruled lines and (b) white pixels are continuously arranged with a predetermined length or more in a primary scanning direction and/or a secondary scanning direction in the extracted halftone dot area 
 a compression processing unit configured to identify other parts than the detected table image and the character image as a background image, and independently compress the detected table image, the character image and the background image in a predetermined coding method; and 
 a file generating unit configured to generate a file that includes the compressed table image, the compressed character image and the compressed background image in respective layers. 
 
     
     
       4. The image processing apparatus according to  claim 3 , wherein the compression processing unit is further configured to convert colors of each cell, each column or each row in the table image to a single color and compress the table image that has the changed color. 
     
     
       5. The image processing apparatus according to  claim 3 , wherein the predetermined length is a maximum size of the character image that can be extracted by the area extracting unit.